Apparatus for polishing semiconductor wafer

ABSTRACT

A wafer planarizing apparatus includes a cleaner that prevents contamination caused by a fume phenomenon occurring when slurry is cleaned from a base of a polishing station. The cleaner has spout holes through which a cleaning solution is applied to a side of a platen of the polishing station. As the cleaning solution flows along the side of the platen, the side of the platen is cleaned. Beneficially, a main body of the cleaner has an arch-shaped upper side so as to stream down foreign materials.

CROSS REFERENCES TO RELATED APPLICATIONS

[0001] This application claims priority under 35 U.S.C. §119 from Korean Patent Application No. 2001-0081318, filed on Dec. 19, 2001, the contents of which are hereby incorporated by reference herein in their entirety for all purposes as if fully set forth herein.

BACKGROUND AND SUMMARY

[0002] 1. Technical Field

[0003] The present invention relates to an apparatus for planarizing a wafer surface during a semiconductor fabricating process and, more specifically, to a wafer polishing apparatus for preventing a contamination caused by a slurry.

[0004] 2. Description

[0005] As semiconductor devices are continuously scaled down, the interconnection structure trends toward a multi-layer structure. Accordingly, a surface step difference between unit cells stacked on a semiconductor substrate becomes increasingly high. In order to reduce the step difference, various methods for planarizing a wafer surface have been proposed.

[0006] Chemical mechanical polishing (CMP) is one method of planarization. A conventional CMP apparatus includes a polishing station and a polishing head assembly. The polishing station has rotatable platens on each of which is mounted a polishing pad. A wafer is placed on a polishing pad that is mounted on a platen. At this time, a wafer surface to be polished (the process surface or polishing surface) faces the polishing pad. The polishing head provides a controllable pressing force (load) onto a rear side of the wafer so as to press the wafer against the polishing pad. A polishing agent (slurry) is supplied to the polishing pad. The platen and the polishing head are moved relative to each other to planarize concave/convex portions of the wafer surface chemically and mechanically.

[0007] During the planarization, the polishing agent may partially drop onto a side of the platen and a base of the polishing station. The polishing station base contaminated by the polishing agent is cleaned by a cleaner (so-called “interplaten cleaner”) as shown in FIG. 1.

[0008] Referring to FIG. 1, a cleaner 50 has first nozzles 52 and second nozzles 54. The first nozzles 52 spray high-pressure deionized (DI) water onto a base 22 of a polishing station 20. The second nozzles 54 clean portions between a retaining ring and a membrane, as well as a polished surface of a wafer.

[0009] The cleaner 50 suffers from the following problems.

[0010] A fume phenomenon is caused by the high-pressure DI water that is sprayed onto the base 22 of the polishing station 20 through the first nozzles 52. Because of the fume phenomenon, the DI water and slurry stick to an uncontaminated device or surface (e.g., a side 24 a of the platen 24) and are hardened. That is, a second contamination occurs.

[0011] Also, unless a surface of the cleaner 50 is itself cleaned frequently, foreign materials (created in grooves 56) lead to a second contamination while the polishing head 30 is cleaned. Moreover, it is difficult to clean the surface of the cleaner 50 because respective spacings between grooves 56 are very narrow.

[0012] In order to overcome the foregoing problems, it is an object of the present invention to provide a wafer planarizing apparatus capable of preventing platen contamination caused by a fume phenomenon that occurs while a base of a polishing station is cleaned.

[0013] Further, it is an object of the present invention to provide a wafer planarizing apparatus capable of minimizing contamination of a cleaner surface, and having a cleaner surface that is easier to clean.

[0014] According to one or more aspects of the invention, a wafer planarizing apparatus includes a polishing station with a base on which a platen having a polishing pad is placed, a polishing head for polishing a wafer on the polishing pad of the platen, and a cleaner mounted upon the base of the polishing station. The cleaner has a main body, and a first cleaning unit that is installed in the main body and cleans the

[0015] The first cleaning unit is spout holes through which a cleaning solution is poured to a side of the platen such that the cleaning solution flows along the side of the platen. The spout holes are formed at the main body adjacent to the side of the platen. The main body has an arch-shaped or inclined upper side so as to stream down foreign materials.

[0016] The cleaner further includes a second cleaning unit for cleaning the base of the polishing station, and a third cleaning unit for cleaning a polished surface of a wafer supported by the polishing head and a carrier head.

[0017] The cleaner further includes a first waterway that is formed at the main body and connected to the first and second cleaning units, a second waterway that is formed at the main body and connected to the third cleaning unit, and first and second cleaning solution supply pipes that are coupled to the first and second waterways to supply a cleaning solution, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 is a partial diagram of a cleaner in a CMP apparatus.

[0019]FIG. 2 is an explosive perspective view of a CMP apparatus including an embodiment of a novel cleaner.

[0020]FIG. 3 is a perspective view of the cleaner shown in FIG. 2.

[0021]FIG. 4 is a front view of the cleaner shown in FIG. 2.

[0022]FIG. 5 is a side view of the cleaner shown in FIG. 2.

[0023]FIG. 6 is a cross-sectional view taken along a line I-I of FIG. 4.

[0024]FIG. 7 is a schematic diagram for explaining the steps of cleaning a cleaner in the CMP apparatus of FIG. 2.

DETAILED DESCRIPTION

[0025] Referring to FIG. 2, a CMP apparatus 100 includes a polishing station 110 and a polishing head assembly 150.

[0026] The polishing head assembly 150 has four polishing heads 152, a driving axis 154, and a motor 156. The polishing head 152 supports a wafer against a polishing pad 122 and uniformly distributes a downward pressure to a rear side of the wafer. The polishing head 152 is rotated by the driving axis 154 connected to the motor 156. The rpm of the polishing head 152 is beneficially from 40 to 70 rpm, but it may be lower. Beneficially, at least two fluid supply channels for supplying an air pressure to the polishing head 152 or for vacuum-absorbing a wafer may be connected to the polishing head 152. Pumps are securely connected to the fluid supply channels, respectively.

[0027] The polishing station 110 has a base 112 upon which rotatable platens 124 are mounted. Polishing pads 122 are placed on the respective platens 124. Each of the platens 124 is connected to platen-rotating means (not shown). Beneficially, the platen-rotating means rotates the platen 124 at 50 to 80 rpm. However, the rotating speed may be lower. The polishing pad 122 may be a composite material having a rough polished surface. The polishing station 110 has conventional pad conditioning means 114 and slurry supply means 116 for supplying slurry onto a polishing pad surface. The slurry contains a reaction reagent (e.g., DI water for oxide polishing), friction articles (e.g., silicon dioxide for oxide polishing), and a chemical reaction catalyst (e.g., potassium hydroxide for oxide polishing). The polishing head assembly 150, the pad conditioning means 114, and the slurry supply means 116 need not be explained in further detail to understand and appreciate the invention.

[0028] The polishing station 110 includes a cleaner 130 that is located between adjacent platens 124. The cleaner 130 cleans the side 124 a of the platen 124 and the base 112 of the polishing station 110 that are contaminated by the slurry during the planarization process, as well as a polished surface of a wafer (not shown) that is supported by the polishing head 152 and a carrier head.

[0029] Referring to FIG. 3 through FIG. 5, the cleaner 130 has a main body 132 and a first cleaning unit 140 formed in the main body 132. The first cleaning unit 140 cleans the side 124 a of the platen 124 adjacent to the cleaner 130. Beneficially, the first cleaning unit 140 has spout holes 140 a through which a cleaning solution is poured.

[0030] Referring to FIG. 7, the cleansing solution poured through the spout hole 140 a flows along the side 124 a of the platen 124 to clean the side 124 a of the platen 124. Therefore, it is possible to prevent slurry from being hardened at the side 124 a of the platen 124. For example, the spout hole 140 a is preferably formed at a side 132 b corresponding to a center of the main body 132 that is closest to the platen 124.

[0031] The cleaner 130 has a second cleaning unit 144 adapted to clean the base 112 of the polishing station 110 and a third cleaning unit 148 adapted to clean a polished surface of the wafer supported by the polishing head 152 and a carrier head. Beneficially, the second cleaning unit 144 has six side nozzles 144 a mounted upon a side 132 b of the main body 132. Also beneficially, the third cleaning unit 148 has six upper nozzles 148 a mounted upon an uppermost portion of an upper side 132 a of the main body 132.

[0032] In the cleaner 130, a cleaning solution is poured through the spout hole 140 while being sprayed at a high pressure through the upper nozzles 148 a and the side nozzles 144 a. Meanwhile, when a spray hole size of the side nozzle 144 a is sufficiently large, a slurry fume can be suppressed even when a high-pressure cleaning solution is sprayed.

[0033] Returning to FIG. 3, beneficially the main body 132 has an arch-shaped upper side 132 a so that any slurry dropping on the main body 132 while cleaning the polishing head 152 and the polished surface of the wafer can naturally flow to the base 112 of the polishing station 110. Advantageously, the main body 132 having the arch-shaped upper side 132 a may minimize a contamination caused by the slurry and enable a worker to easily clean a surface of the cleaner as compared to the effort required to clean a conventional cleaner. For example, in the embodiment of FIG. 3, it can be seen that the upper side 132 a of the main body 132 is arched or inclined.

[0034] Referring to FIG. 5 and FIG. 6, the cleaner 130 has first and second fluid pathways 134 and 136 formed in the main body 132. The first fluid pathway 134 is connected to the spout holes 140 a and the side nozzles 144 a, and the second fluid pathway 136 is connected to the upper nozzles 148 a. First and second cleaning solution supply pipes 137 and 139 for supplying a cleaning solution are connected to the first and second fluid pathways 134 and 136, respectively. For example, the cleaning solution is supplied to the first and second cleaning units 140 and 144 through the first cleaning solution supply pipe 137 at a predetermined interval (for example, for 60 seconds at an interval of 900 seconds). The cleaning solution is supplied to the third cleaning unit 148 through the second cleaning solution supply pipe 139 by the handling of a worker.

[0035] Disclosed herein therefore is a cleaner for preventing a platen contamination caused by a fume phenomenon occurring when a base of a polishing station is cleaned. Further, the cleaner has a main body having an arch-shaped upper side so as to minimize a contamination caused by slurry. Still further, the cleaner has spout holes through which a cleaning solution is poured to a side of the platen. The spout holes are formed in the cleaner. As the cleaning solution flows along a side of a platen, the side of the platen is cleaned.

[0036] As described above, it is possible to prevent a platen contamination caused by a fume phenomenon occurring when a base of a polishing station is cleaned. Further, since a cleaner has an arch-shaped upper side, a main body contamination caused by slurry can be minimized and a worker can easily clean the cleaner as compared to the effort required to clean a conventional cleaner. In addition, since a cleaning solution cleans a side of the platen while flowing along the side of the platen, the slurry is not hardened on the side of the platen.

[0037] While the invention has been illustrated and described in detail in the foregoing drawings and description, the same is to be considered as illustrative and not restrictive in character, it being understood that only preferred embodiments thereof have been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected. 

What is claimed is:
 1. A wafer planarizing apparatus comprising: a polishing station with a base on which a platen having a polishing pad is placed; a polishing head for polishing a wafer on the polishing pad of the platen; and a cleaner disposed upon the base of the polishing station, wherein the cleaner has a main body and a first cleaning unit installed in the main body, the first cleaning unit being adapted to clean a side of the platen.
 2. The wafer planarizing apparatus of claim 1, wherein the first cleaning unit includes at least one spout hole adapted to pour a cleaning solution to the side of the platen such that the cleaning solution flows along the side of the platen.
 3. The wafer planarizing apparatus of claim 2, wherein the spout hole is formed in the main body adjacent to the side of the platen.
 4. The wafer planarizing apparatus of claim 1, wherein the main body is located between adjacent platens.
 5. The wafer planarizing apparatus of claim 1, wherein the main body has an arch-shaped upper side.
 6. The wafer planarizing apparatus of claim 1, wherein the main body has an inclined upper side so as to stream down foreign materials.
 7. The wafer planarizing apparatus of claim 1, wherein the cleaner further includes: a second cleaning unit adapted to clean the base of the polishing station; and a third cleaning unit adapted to clean a polished surface of a wafer supported by the polishing head and a carrier head.
 8. The wafer planarizing apparatus of claim 7, wherein the second cleaning unit includes second nozzles disposed at a side of the main body.
 9. The wafer planarizing apparatus of claim 7, wherein the main body has an arch-shaped upper side, and the third cleaning unit includes a plurality of third nozzles disposed at the arch-shaped upper side.
 10. The wafer planarizing apparatus of claim 7, wherein the cleaner further includes: a first waterway fluid pathway disposed in the main body and connected to the first and second cleaning units; a second fluid pathway disposed in the main body and connected to the third cleaning unit; and first and second cleaning solution supply pipes that are coupled to the first and second fluid pathways to supply a cleaning solution, respectively.
 11. The wafer planarizing apparatus of claim 10, wherein the first cleaning solution supply pipe supplies the cleaning solution in a manual manner.
 12. The wafer planarizing apparatus of claim 1, wherein the cleaning solution employs deionized water (DI water).
 13. A wafer planarizing apparatus, comprising: a polishing station, comprising, a base, a platen mounted on the base, the platen having a polishing means thereon; and a polishing head adapted to polish a wafer on the polishing means; and a cleaner disposed on the base of the polishing station, the cleaner having a first cleaning unit adapted to apply a cleaning solution to clean a side of the platen.
 14. The apparatus of claim 13, wherein the cleaner includes a main body having an upper side that is arched.
 15. The apparatus of claim 13, wherein the cleaner further comprises a second cleaning unit adapted to clean the base of the polishing station.
 16. The apparatus of claim 15, wherein the cleaner further comprises a third cleaning unit adapted to clean a polished surface of a wafer.
 17. The apparatus of claim 16, wherein the cleaner further includes: a first fluid pathway connected to the first and second cleaning units; and a second fluid pathway connected to the third cleaning unit.
 18. The apparatus of claim 13, wherein the cleaner further includes a fluid pathway connected between the first cleaning unit and a cleaning solution supply pipe.
 19. The apparatus of claim 13, wherein the cleaner comprises a main housing and the first cleaning unit includes a main spout formed in the housing. 